Wear Tendency Research Articles

Machine learning models and machinability analysis for comparison of various cooling and lubricating mediums during milling of Hardox 400 steel

Martensitic steels are widely used in many areas such as automotive, mining, and agriculture mostly thanks to their thermal loading ability property. On the other hand, these special steels exhibit extreme tool wear tendency and low surface quality which can be associated with abrasive resistance. This situation makes this steel hard-to-cut and requires further investigation with several approaches. Sustainable machining environments are highly effective as modern strategies to improve the machinability index. Also, machine learning models have pivotal role on decreasing the total consumption in the way of lean manufacturing. In the light of above-mentioned information, this work focuses on the machining performances and optimization of dry, flood, and MQL conditions during the milling of Hardox 400 martensitic stainless steel. A novel approach was applied with using several cutting environments and machine learning models to enhance machinability of Hardox which is an industrially important material. Results were analyzed with different machine learning models using heat map and decision trees. Seemingly, cutting fluid assistance in the milling of Hardox steel is critical where flood and MQL provided a considerable effect on the tool wear for reducing it under some level. Also, this technology was found useful in determining the best conditions of machinability in terms of surface roughness, chip morphology, energy consumption, and cutting temperatures. Machine learning models provided hopeful results in analyzing the correlations between parameters used in the model. In machine learning, the heat map being close to 1 and the MSE and MAE values being close to 0 indicated that the model was suitable. This study is expected to observe the contributions of different types of cutting environments to the machinability criteria during milling of industrially important materials.

Investigation of the machinability of B4C+TiB2/Al 2024 composite manufactured by powder metallurgy with EDM

In this study, the machinability of B4C and TiB2 reinforced Al 2024 based composites produced by powder metallurgy was investigated with EDM (Electro Discharge Machining) method using two different copper electrodes. For this purpose, composite samples were produced at 6% TiB2+12% B4C reinforcement ratios. Then, scanning electron microscopy images were taken to examine the microstructure of the composite samples. Also EDAX analyzes were performed during SEM images. In EDM machinability experiments of the composite material two different electrodes; pure copper and beryllium copper were used. The experiments were carried out using three different current (I) and arc pulse on time ( ton) and two different arc pulse off time ( toff) parameters. As a result of EDM experiments, roughness measurements of the machined surfaces were made and SEM images of the machined surfaces were taken again. According to the experimental findings, material removal rate increased in machining with CuBe tool compared to machining made with pure Cu and CuBe tools showed higher wear tendency than Cu tool sunder the same machining conditions and roughness values in CuBe electrodes were lower than machining made with pure Cu. And the roughness values of CuBe are lower than the machinings with pure Cu.

Investigation of the Effects of Cooling and Lubricating Strategies on Tribological Characteristics in Machining of Hybrid Composites

Engineering materials are expected to contain physical and mechanical properties to meet the requirements and to improve the functionality according to their application area. In this direction, hybrid composites stand as an excellent option to fulfill these requests thanks to their production procedure. Despite the powder metallurgy method that allows for manufacturing products with high accuracy, machining operations are still required to obtain a final product. On the other hand, such materials are characterized with uncertainties in the structure and extremely hard reinforcement particles that aggravate the machinability. One of the prominent solutions for better machinability of composites is to use evolutionary cooling and lubricating strategies. This study focuses on the determination of tribological behavior of Cu-based, B-Ti-SiCP reinforced, about 5% wt. hybrid composites under milling of several environments, such as dry, minimum quantity lubrication (MQL)-assisted and cryogenic LN2-assisted. Comprehensive evaluation was carried out by considering tool wear, temperature, energy, surface roughness, surface texture and chips morphology as the machinability characteristics. The findings of this experimental research showed that cryogenic cooling improves the tribological conditions by reducing the cutting temperatures, flank wear tendency and required cutting energy. On the other hand, MQL based lubricating strategy provided the best tool wear index and surface characteristics, i.e., surface roughness and surface topography, which is related to spectacular ability in developing the friction conditions in the deformation zones. Therefore, this paper offers a novel milling strategy for Cu-based hybrid composites with the help of environmentally-friendly techniques.

Tribological Behaviour of an Automotive Brake Pad System Under Los Angeles City Traffic Test Conditions

<div class="section abstract"><div class="htmlview paragraph">The Los Angeles City Traffic (LACT) brake test is well known acclaimed procedure used by many vehicle manufacturers to assess the brake pad wear behavior and to investigate the Noise, Vibration and Harness (NVH) performance of the brake system. The LACT driving route consists of a set of real-world driving conditions, which has been considered representative of the US passenger vehicle market.</div><div class="htmlview paragraph">The scope of this study is to mimic the LACT test using finite element analysis (FEA) to calculate the wear displacement based on Rhee’s theory. The Leading-edge and trailing edge of the brake pad’s wear tendency is also predicted from the simulation. The finite element model for wear simulation consists of brake system viz., Rotor, Knuckle, Pads, Anchor bracket, Piston, and Caliper. Various braking scenarios consist of different driving characteristics (Number of brake applications, vehicle speed, brake pressure, rotor temperature, and brake rotor interface friction variation) based on LACT Route traffics are replicated in FEA.</div><div class="htmlview paragraph">The wear displacement results from the finite element analysis are in good agreement with physical test results. Further, based on the wear displacement values, the brake pad’s life span is calculated and correlated well with the test measurements.</div></div>

Mechanical characterization of aluminium 6061 hybrid metal matrix composites

Bigger interest in utilizing Metal Matrix Composites (MMCs) research on MMCs has provided not only new types of hybrid metal matrix composites, but also characterizations of their physical, thermo-mechanical, and tribological properties over the past 30 years. The main objective of this research is to produce MMCs with enhanced strength and wear resistance, that to replace the traditional heavy weight metals and alloys. In this research the parent material chosen was AA6061 aluminium alloy which has a wide commercial application and the reinforcements (SiCp/Fly ash/Glass Fibre) which can increase the wear tendency and in addition to that glass fibre is used to improve the biaxial strength of the prepared MMC. The work presented here uses Silicon carbide as the material, fly ash and glass fibre reinforced aluminium alloy (Al6061) composites, processed by stir casting route was used. The required quantities of silicon carbide (10 g and 15 g) and fly ash (10 g and 15 g) were taken in a powder container and the composites were prepared by using the stir casting process. This new material is evaluated through a limited mechanical test that Tensile, Hardness and Wear and to strengthen the experimental process SEM images are taken before and after the tests. The addition of reinforcement in Aluminium 6061 hybrid metal matrix composites, the tensile strength increases in the specimen 1 10 g of reinforcement mixed with A6061 and as well as in the specimen-2 15 g of reinforcement mixed with A6061 and wear resistance increases gradually and also wear and hardness in specimen 2 gives moderate result but the tribological behaviour is good.

A critical review on wear and corrosion of carbide free bainitic steel

Different research on wear and corrosion of CFB (carbide free bainitic steel) over the past two decades has enabled a better understanding and advanced applications of CFB steel. With the help of advanced testing techniques, and equipment the detailed study of microstructure and nanostructured steels has been possible. The earlier years were focused on comparison of the bainite steel with the steel which is quenched and tempered (QT) for identifying the wear tendencies and comparison between carbon free bainite and martensite for the corrosive behavior of the carbide free bainitic steel. Later the trend shifted towards the nanostructured analysis from microstructure analysis with the improvement in the instruments. Advancements like HT-CAT i.e., high temperature continuous abrasion tester have an important role to play, the mechanism of material removal rate studied. There has also been development in alloying the bainite to reduce the corrosion rate and give more strength. Current trends in the form of study of wear and corrosion of carbide free bainitic steel and future needs are discussed hereby.

Numerical Simulation for the Optimization of Polygonal Pin Profiles in Friction Stir Welding of Aluminum

The tool with polygonal pin profile has been widely employed in friction stir welding (FSW) of aluminum, but there is hardly an effective optimization methodology existed as the thermomechanical characteristics affected by pins with various flats number have not been understood comprehensively. Therefore, the present work employs a 3-dimensional computational fluid dynamics (CFD) model to have an integrated observation of the FSW process with the effect of polygonal pin profiles. Both the heat generation modes due to contact friction at the tool–workpiece interface and volumetric viscous dissipation in the vicinity of the tool are considered. The model is utilized to give a quantitative analysis of the heat generation, temperature distribution, plastic material flow and welding loads during the FSW process for various tools with polygonal pin profiles, as well as a variety of shoulder diameters, welding speeds and tool rotation speeds. The calculated results of thermal cycles, tool torques and joint cross sections for some typical polygonal pins and welding parameters are all found to be compared well with the experimental ones, which demonstrates the feasibility and applicability of the present numerical model. Particularly, a methodology is developed for the optimization of the flats number by identifying the torque components in both parallel and vertical direction of the pin-side flat region. The results show that the optimized pin flats number increases with increasing tool rotation speed, while the influence of both welding speed and shoulder diameter can be supposed to be insignificant. Moreover, the dependability of the optimized results is also discussed by considering wear tendency and service life of the pin for multiple welding conditions.

Mechanical and wear characterization of LM13/SiC/Gr dispersed hybrid composites formed through stir casting

The modern engineering technology requires materials with high strength, less weight, immense stiffness and superior mechanical properties. Aluminium depended MMCs find diverse applications in defence, aerospace, military, automotive, equipment’s related to electronics and sports for their favorable characteristics. The present investigation focuses on development and characterization of LM13 alloy reinforced with distinct weight ratio of Silicon Carbide (SiC) and Graphite (Gr) hybrid MMCs using conventional casting procedure. The casted samples were designed for the essential testing according to ASTM basic. The properties such as hardness and strength due to tensile behaviour of the manufactured MMCs were discerned by carrying experiments while the wear characteristics were examined via the pin-on-disc technique. Microstructural images reveal the presence of reinforcements and homogeneous distribution over the matrix material. Microhardness and tension characteristics disclosed that the developed hybrid aluminium MMCs had met with a melioration of 11.85% and 24.82% respectively, compared with monolithic matrix. Wear tendencies were pondered by varying load (10–50 N), sliding speed (0.4–2 m/s) and sliding distance (400–2000 m). Statistical interpretation was enacted utilizing Analysis of Variance (ANOVA) procedure to obtain the most appropriate wear approach range for amassing uttermost wear resistance. Experimental data reveal that wear resistance inflation with enhancement in sliding speed, load & sliding distance. Outcomes disclosed that optimum rate of wear (WR) and Frictional coefficient (COF) was obtained at 0.8 m/s, 800 m & 20 N.

Fracture and wear mechanisms of FeMnCrNiCo + x(TiC) composite high-entropy alloy cladding layers

FeMnCrNiCo + x(TiC) composite high-entropy alloy (HEA) coatings were manufactured by laser cladding. Then the small punch and wear experiments at room temperature were conducted. The phases and microstructures of the composite HEA coatings were characterized using XRD, SEM/EDS, EBSD and TEM, and the strengthening, fracture and wear mechanisms of coatings were systematically analyzed and discussed. The results showed that small-sized particles and large-sized particles in coatings reduced the nucleation energy barrier of grain, and particles precipitated at grain boundaries hindered the movement of grain boundary. And the refined grain and increased dislocation density enhanced the capability of coatings to resist potential plastic deformation. As for the properties, the strength of the coating with 5 wt% TiC was increased, but cracks easily initiated and propagated around the precipitated particles at grain boundaries, which lowered the toughness. The excess TiC made the brittle and large-sized particles become cracking sources in coatings, thus the strength and toughness of coatings were deteriorated. Obvious fatigue wear tendency in these two coatings (5 wt% & 10 wt%) influenced their service life in the wear environment, although the coating with 10 wt% TiC had better surface wear performance.

Tailoring Tribological Performance of Pure Titanium by a Duplex Treatment of Laser Surface Texturing-Thermal Oxidation

A combined surface treatment of laser surface texturing (LST)-thermal oxidation (TO) technique was performed on pure titanium (TA2) matrix to enhance its wear resistance. The dimple-shaped texture was fabricated by using an optical fiber laser processing equipment, and the dimple-shaped texture with diameter of 300 μm and density of 5%. The thermal oxidation coating (TO-coating) was prepared by TO treatment under 650 °C for 30 h. Microstructure, microhardness, and bonding strength of the TO-TA2 were systematically characterized. Comparative evaluation of anti-wear performance for relevant samples of duplex treatment TA2 (DT-TA2), LST-TA2, TO-TA2, and TA2 matrix were investigated via the dry sliding process. The results revealed that uniform and dense TO coating with a thickness of approximately 11 μm was fabricated on the surface of the TA2 matrix. The attained TO coating consisted of the compound phase of TiO2 shown by XRD detection. The surface hardness and elasticity modulus of the TA2 were improved by TO treatment, and the attained TO coating had a strong bonding strength with the TA2 matrix. In terms of wear rate, the samples were sorted in the following order: DT-TA2 < TO-TA2 < LST-TA2 < TA2. For tribological behavior, the duplex treatment process can significantly reduce the abrasive wear and adhesive wear tendency of the TA2 matrix. Taking advantage of LST and TO treatment, the wear resistance of TA2 sample after duplex treatment was significantly improved. In view of this, the TO coating is expected to provide wear resistance protection for pure titanium components, the presence of dimples reduced the friction coefficient of pure titanium components, and further extended their service life. The results may provide reference data for surface modification of TA2 by the laser surface texturing and thermal oxidation duplex treatment.

Optimizing the tool pin with three flats in friction stir welding of aluminum alloy

The role of tool pin profile is crucial in friction stir welding (FSW) process, but its optimization design still requires sufficient quantitative data and a comprehensive understanding of the thermomechanical behavior around the tool. The present work gives a systematic investigation of FSW process for tool pin with three flats by using a three-dimensional computational fluid dynamics model. The thermal response, material flow behavior, and welding loads are analyzed for tool pin with various proportion of the flat feature. The feasibility of the numerical model is verified by comparing the results with measured thermal cycle, macrostructure, tool torque, and traverse force for both tool pins with and without flat feature. Based on the numerical model, a methodology is proposed for the optimization design of tool pin profile with three flats by identifying different torque components on flat area, and also considering the material flow behavior and tool wear tendency. Furthermore, the proposed methodology is utilized for optimizing tool pin profile for a wide range of process parameters, and the precision of the optimization result is also discussed. The present approach provides an explicit solution for the computer-aided optimization design and reliability assessment of the tool pin profile in FSW.

Analysis on wheel wear tendency of railway vehicle considering worn tread shape

Analysis on wheel wear tendency of railway vehicle considering worn tread shape

Computational Wear Prediction for Impact of Kinematics Boundary Conditions on Wear of Total Knee Replacement Using Two Cross-Shear Models

Abstract Wear particle-induced osteolysis is the main reason for the long-term failure of total knee replacement. Simulator testing is the standard procedure for validating wear performance pre-clinically. The load and kinematics specified in the International Organization for Standardization (ISO) are standard input profiles for wear testing of implants. Directions of internal–external (IE) rotation and anterior–posterior (AP) translation have been modified in the new version of ISO 14243-3 2014. This study focused on investigating the effects of internal–external rotation and anterior–posterior translation on the wear of knee implants. Numerical wear prediction was performed using the finite element model along with two wear models, namely the contact pressure independent model and contact pressure dependent model. Addition of internal–external rotation significantly increased the wear, and the two wear models obtained similar results. The effect of internal–external rotation direction on wear was slight. Forward movement of the tibial insert during flexion decreased the wear under the contact pressure independent model and increased the wear under the contact pressure dependent model. When the AP direction switched, the two models obtained opposite wear tendencies. The results predicted by the contact pressure dependent model were consistent with those of wear tendency experiments reported in the literature. Further investigation of wear physical principles was necessary to gain a more reliable model. This study demonstrated that both internal–external rotation and anterior–posterior translation were pivotal factors influencing the contact mechanism and wear of total knee implants. More realistic kinematics are necessary for accurate wear assessment.

Evaluating the Wear of Polycrystalline Diamond Compact Drill Bit Cutters using Indentation and Scratch Tests

Abstract–Polycrystalline diamond compact (PDC) drill bits are widely used in oil and gas drilling. The wear of PDC cutters is a major problem during drilling. It leads to severe time losses which affect the overall drilling operation cost. Therefore, it is essential to evaluate the wear tendency for these cutters using predictive approaches. The present research is focused on studying the wear mechanisms of PDC cutters and the effect of their mechanical properties on the extent of wear. The volume of wear for the PDC cutters was determined experimentally using micro- and nano-scratch tests by implementing an approach based on the geometry of the removed material after micro- and nano-scratch tests. The experimental wear results were compared to the predictions from current models in the literature.Various wear models are evaluated for micro- and nano-scratch tests on both layers of the PDC samples. The study shows that the wear of the PDC cutters can be predicted from the material mechanical properties, applied load, sliding distance, and hardness of the PDC cutters. The study could be extended for the evaluation of wear intensity of PDC cutters from various manufactures without using the previous techniques of abrasion testing.

Suitability of the full body ceramic end milling tools for high speed machining of nickel based alloy Inconel 718

Sustainability of machining processes is becoming increasingly important today. Therefore, the use of conventional machining with oil based cooling lubrication fluids (oil CLF) is becoming insufficient. On the other hand, dry machining, as the cleanest and most environmentally friendly machining process, lacks in cooling and lubrication. This can shorten tool life and decrease productivity, especially when machining difficult-to-cut materials. Machining these materials is often affected via high mechanical and thermal tool loads. Workpiece material characteristics like low thermal conductivity, strain hardening, etc. are causing high temperatures in the cutting zone and consequently high wear tendency of carbide tools, even at relatively low cutting speeds. Therefore, to increase productivity, as an alternative to carbide tools, full body ceramic milling tools are proposed. Ceramic, as a cutting material, is stable even at high temperatures, which are present when machining difficult-to-cut materials, such as nickel based alloy Inconel 718. Hardness retaining (high compressive strength), good wear resistance and chemical stability at high temperatures are other pros of ceramic tools.In this paper, high speed milling process using full body ceramic end milling tools is analyzed in parallel to carbide tools. Tool life of ceramic end mills is compared with tool life of more widely used carbide end mills when milling difficult-to-cut nickel based alloy Inconel 718. The results show that ceramic milling tools are offering an increase in productivity, however, the overall efficiency, in comparisons to carbide tools, is still questionable.

Sliding wear characteristics of solid lubricant coating on titanium alloy surface modified by laser texturing and ternary hard coatings

Titanium alloys are poor in wear resistance and it is not suitable under sliding conditions even with lubrication because of its severe adhesive wear tendency. The surface modifications through texturing and surface coating were used to enhance the surface properties of the titanium alloy substrate. Hard and wear resistant coatings such as TiAlN and AlCrN were applied over textured titanium alloy surfaces with chromium as interlayer. To improve the friction and wear resisting performance of hard coatings further, solid lubricant, molybdenum disulphide (MoS2), was deposited on dimples made over hard coatings. Unidirectional sliding wear tests were performed with pin on disc contact geometry, to evaluate the tribological performance of coated substrates. The tests were performed under three different normal loads for a period of 40 min at sliding velocity of 2 m/s. The tribological behaviours of multi-layer coatings such as coating structure, friction coefficient and specific wear rate were investigated and analyzed. The lower friction coefficient of approximately 0.1 was found at the early sliding stage, which reduces the material transfer and increases the wear life. Although, the friction coefficient increased to high values after MoS2 coating was partially removed, substrate was still protected against wear by underlying hard composite layer.

Converting the pneumatic to servo-based system in resistance spot welding: Analyzing the electrode caps deformation

In this experimental research, the electrode caps are investigated for deterioration under the resistance spot welding technology. The research was fundamentally conducted using two different electrode actuation systems to understand the wear and tear factors of electrode caps. A Japanese model 75 kVA pedestal, alternating current waveform of spot welder, was engaged to carry out the welding processes up to 900 welding attempts on pneumatic system. Subsequently, it was converted into servo-based electrode actuating systems and repeated the entire welding processes. The carbon and stainless steel sheets are primarily used to weld in this experiment. The electrode caps are then sharpened by CDK-R dresser to remove the mushroom growth which has regularly been induced for every 400 welding attempts. As for the macrograph and micrograph observations, the electrode caps are measured for diameter growth of electrode caps as well as the copper-to-chromium ratio. The chromium content has been significantly reduced at the electro tip areas due to the direct expose of heat generation which becomes a regular phenomenon in both the systems. However, the results from servo-based system are deemed to be offering lower tendency of wear and tear factors when compared to the pneumatic-based system.

Experimental Investigation of aluminum doping crumb rubber/epoxy composite in reciprocating motion

The experimental investigation of reciprocating motion between the aluminum doped crumb rubber /epoxy composite and the steel ball has been carried out under Reciprocating Friction Tester, TR-282 to study the wear and coefficient of frictions using different normal loads (0.4Kg, 0.7Kgand1Kg), differentfrequencies (10Hz, 25Hz and 40Hz).The wear is a function of normal load, reciprocating frequency, reciprocating duration and the composition of the material. The percentage of aluminum presents in the composite changesbut the other components remain the same.The four types of composites are fabricated by compression molding process having 0%, 10%, 20% and 30% Al. The effect of different parameters such as normal load, reciprocating frequency and percentage of aluminum has been studied. It is observed that the wear and coefficient of friction is influenced by the parameters. The tendency of wear goes on decreasing with the increase of normal load and it is minimum for a composite having 10%aluminum at a normal load of 0.7Kg and then goes on increasing at higher loads for all types of composite due to the adhesive nature of the composite. The coefficient of friction goes on decreasing with increasing normal loads due to the formation of thin film as an effect of heat generation with normal load.

에폭시 프라이머 도료의 에어리스 스프레이 분사 시간에 따른 팁 노즐 침식마모경향과 분사특성 연구

Airless spray which is widely used for painting to ship blocks and hull sides is the coating method for attaching atomized paint material to the substrate using spray tip nozzle with compressed air. When the paint material which has high solid contents such as epoxy primer paint is atomized by passing through spray tip nozzle with high pressure, the nozzle composed of tungsten carbide(WC) undergoes the erosive wear, leading to widening of nozzle hole. The deformation of nozzle hole induces improper spray pattern and coating failures such as finger pattern and sagging because the conditions of spray pump pressure and paint flow rate for developing full spray pattern are changed. In this study, an appropriate replacement cycle of spray tip was predicted by measuring the erosive wear tendency as increasing the spraying time of epoxy primer paint.

Determination of early failure sources and mechanisms for Al 99.7% and Al–Mg–Si alloy bare conductors used in aerial transmission lines

In this article, early failure reasons and their sources for the bare aerial transmission line conductors have been presented with a combination of measuring data on wear tendency of their components and analyzing of collected samples due to processing damages and continue cast defects onto wires produced by 99.7% EC grade Al and Al–Mg–Si alloys. Nominal service life of aerial conductors is 30years. However most of them are failed early. Essential source of the failure depends on environmental conditions and manufacturing process. After installation of conductors to trusses, the fretting phenomenon between strands under greased and non-greased applications is triggered due to fluctuation of bending, tension and torsional stresses by wind and dead loads of conductors. Environmental forcing functions cause working of surfaces of defected and processing damaged wires each other with small displacements and create grinding of small particles and finally fretting. Samples collected from the aerial conductor plant including processing defects and damages were illustrated and interpreted in the article deeply. Additionally, tribological behaviors of conductor wires were also investigated with different parameters under grease lubrication and dry friction conditions. Results were presented in graphics and figures in details to indicate the early failure reasons which were mainly related to manufacturing process and tooling used in processing of them.